This invention concerns the determination and control of the weight of hay bales during the baling process.
The weight of individual bales of hay during the baling process is a critical variable which affects the marketability of the bales in several ways. These include such factors as freight cost from production site to market location, suitability of the bales for the horse hay market versus the dairy market or other uses, quality of the baled hay, and others. In addition, continuous weighing of bales allows production tonnages to be immediately calculated and made available to management for production inventory purposes.
Individual bale weight can be determined in several ways. For example, each bale can be individually weighed while momentarily stationary as it exits the baler. This method is labor intensive to the point of prohibiting it as a practical expedient. Alternatively, some type of force-detecting device may be attached to the exit chute of the baler to determine the weight of moving bales. Suitable force-detecting devices include strain gauge load cells, spring and hydraulic activated scales, weighted balance beams, and other devices. The latter method, although in use to some degree, suffers from the disadvantages of inaccuracy due to vibration and severe maintenance problems because of the very harsh baler environment.
Conventional hay baler machines are generally comprised of: (a) a driver's compartment, (b) a feeder mechanism which picks the hay up from the ground, (c) a section which distributes the hay to form a relatively uniform stream, (d) a forming chamber wherein the stream is compacted and formed into the desired shape and size, and (e) a squeeze rail region where the shaped stream is further compacted and wrapped with wire or twine to form the finished bale which is discharged onto the ground. The forming chamber and squeeze rail region, which may be generically characterized as compression zones, have flat retaining walls against which the hay slides as it advances through the baler. The hay will generally pass through said compression zones at a linear flow velocity of between about 150 and 500 inches per minute. The flow is substantially continuous, although having in certain instances a uniformly pulsed motion caused by the compacting mechanisms. Finished bale density varies from approximately 8 to 15 pounds per cubic foot.
The dependence of bale weight upon bale moisture content has long been recognized by baler manufactures. For a given hay baler, the higher the moisture of the hay passing through the baler, the heavier the bale will be. This is due to several factors, namely: (a) the additional weight which the moisture adds to the hay; (b) the greater coefficient of friction with respect to the baler walls; and (c) the softer, more compliant nature of the wet hay which makes it more compressible at a given pressure.
The moisture level of a given windrow of hay is often not uniform throughout its length. This is caused by factors such as ground terrain (hay located in swales is usually of higher moisture content than hay located on ridges), ground moisture, quantity of weeds contained in the hay, windrow size, and other factors. Therefore, the weights of bales in a given field will vary as the moisture content varies if no adjustments are made during baling to compensate for fluctuations in the moisture content of the hay being baled.
In order for the baler operator to have control of the weight of bales being produced, the side walls and/or top and bottom walls of the compression chamber are constructed to be adjustable so that the distance of separation between opposed walls can be varied. By virtue of the construction of the baler and its manner of operation, the pressure applied to the hay increases as the distance between opposed walls diminishes, (thus increasing or decreasing the friction force between the hay and the compression chamber walls). The adjustment of the wall spacing results in bales which are more or less dense and which thus weight more or less. In this manner, as the moisture content of hay which is being baled increases, causing the friction coefficient and therefore the bale weight to increase, the baler operator can reduce the wall pressure on the hay and maintain a constant bale weight at a given bale size.
The adjustment of the spacing between the walls is generally controlled through either a hydraulic ram or through a hand adjustable squeeze mechanism. Although the baler operator has control of the bale weight, no satisfactory method of measuring the weight of each bale being produced has been designed.
It is accordingly an object of this invention to provide a bale weight monitoring system which is continuous in nature and which is directly associated with the baler such that every bale which is baled may be immediately checked for bale weight.
It is another object of this invention to provide a method utilizing a system as in the foregoing object which determines bale weight during the baling process so that appropriate adjustments can be made to retain the bale weight within acceptable limits.
It is another object of this invention to provide a method of adding water to a bale in cases where hay being baled is of too low moisture content, and to control the amount of water being added by continuously monitoring the moisture content of the hay.
It is a further object of this invention to provide a method of the aforesaid nature which provides an output signal dependent on the weight of individual bales being formed during the baling process, said signal serving to control the hydraulic ram or rams to provide a uniform bale weight.
It is a still further object of the present invention to provide a system of the aforesaid nature comprised of apparatus components of rugged, durable construction capable of withstanding the corrosive, abrasive conditions prevalent within and about a hay baler.
It is yet another object of the invention to provide apparatus components of the aforesaid nature amenable to low cost manufacture and facile installation into conventional hay baling equipment.
It is a further object of this invention to provide a method of the aforesaid nature which provides an output signal dependent on the moisture content of the hay, said signal serving to control the amount of water added to the bale in cases where the hay is too dry.
These objects and other objects and advantages of the invention will be apparent from the following description.